<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    {% block title %}{% endblock %}
    <style>
        .header{
            width:1000px;
            height:100px;
            background:red;
            display:flex;
            justify-content:center;
            align-items:center;
            font-size:2rem;
        }
        .content{
            float:left;
            width:800px;
            height:500px;
            display:flex;
            justify-content:center;
            align-items:center;
            font-size:3rem;
        }
        .content:hover{
            font-weight:bold;
        }
        .nav{
            float:left;
            width:200px;
            height:500px;
            background:skyblue;
            display:flex;
            justify-content:center;
            align-items:center;
            font-size:2rem;
        }
        .footer{
            width:1000px;
            height:100px;
            background:green;
            display:flex;
            justify-content:center;
            align-items:center;
            font-size:2rem;
        }
        .page02{
            background:lightpink;
        }
        .page01{
            background:gold;
        }
    </style>
</head>
<body>
    <div class="header">Header</div>
    {% block content %}{% endblock %}
    <div class="nav">Nav</div>
    <div class="footer">Footer</div>
</body>
</html>